It is known that such structures are generally composed of fixed and/or telescopic elements formed by pairs of arches between which panels of a flexible and usually transparent or translucent material are fitted. Some of the panels themselves are maneuverable so that each element may be at least partially uncovered.
Additionally, depending on the desired specifications, the elements themselves may be either fixed or horizontally mobile, sliding into each other in a telescopic fashion.
The arches forming each element are made from a curved, generally enameled-aluminum profile bearing on its lateral faces several grooves designed to support the flexible panels and guide their movement.
Thus, a French patent (FR-A-2 627 530) describes a profile of the type mentioned above that bears, on each of its lateral faces, parallel fins arranged one above the other to form at least three guide grooves. The upper grooves of the profile, which hereinafter shall refer to those grooves situated on the side of the profile with the longest radius of curvature, receive the panels that form the roof section of the element. These roof-section panels are generally fixed in position between the pair of arches that supports them and are usually thicker than the maneuverable panels that form the lateral walls of the structure. In particular, “roof-section” panels may be made from a material having a cellular structure.
The lower grooves of the profile, which hereinafter shall refer to those grooves situated on the side of the profile with the shortest radius of curvature, receive panels that form the vertically maneuverable lateral walls of the element. These panels can be partially raised towards the roof section of the element or lowered to the ground.
These lateral-wall sliding panels are generally made from a solid, transparent material such as polymethyl methacrylate resin or polycarbonate resin. As such, the weight that must be raised vertically in order to partially uncover the lateral parts of each element of the structure is far from negligible.
Moreover, the flexible panels most often used to make each element of such covering structures are flat, regardless of whether the element is intended to be mobile or not. The variable curvature of the panels in the assembled element is obtained when the panels are fitted into place between the curvilinear supporting arches. Consequently, the lateral edges of the panels come naturally into contact with the inner walls of the guide grooves into which they are fitted so that, with repeated maneuvering of the lateral-wall panels (raising and lowering), scratching tends to occur along the edges of the panels in contact with the supporting profiles.
It is also known that, for reasons essentially due to the expansion of the panels, the distance between the two arches forming an element should be greater than the width of the panels, regardless of whether the latter are intended to be fixed (as they are when used as roof-section panels) or vertically maneuverable (as they are when used to form the lateral walls of the structure). As such, there is a tendency for lateral-wall panels to shift slightly from side to side so that the scratch marks along the lateral edges of the panels are apparent over several millimeters on each lateral edge of these maneuverable panels. From an aesthetic point of view, this constitutes a defect that is difficult for users to accept.
Additionally, on account of the friction that accompanies the movement of these lateral-wall panels in their guide grooves, maneuvering the panels requires a greater effort on the part of the user.